Inter-annual and body topographic consistency in the plumage bacterial load of Great tits

Plumage bacteria may play an important role in shaping the life histories of birds. However, to design suitable experiments to examine causal relationships between plumage bacteria and the fitness of host birds, natural variation in plumage bacterial communities needs to be better understood.We examined within-individual consistency of plumage bacterial contamination in Great Tits (Parus major), comparing different body regions (ventral vs. dorsal) and comparing contamination between years. Numbers of free-living and attached bacteria and the species richness of feather-degrading bacterial assemblages were studied using flow cytometry and ribosomal intergenic spacer analysis (RISA). Numbers of both types of bacteria were higher on dorsal than on ventral feathers. Numbers of free-living, but not attached, bacteria on the two body regions were highly positively correlated. There was also a strong within-individual correlation between numbers of attached bacteria during the same breeding stages in different years. These results suggest that, despite variation in absolute levels of feather bacterial loads between years and different body regions, sampling individual birds can provide reliable estimates of relative levels of bacterial contamination, as long as sampling time and body region are carefully standardized.Las bacterias del plumaje pueden jugar un papel importante en el moldeamiento de las historias de vida de las aves. Sin embargo, para diseñar un experimento adecuado que examine la relación efecto causa entre las bacterias del plumaje y el éxito de las aves hospederas, se necesita entender mejor la variación natural de la comunidad de bacterias en el plumaje. Examinamos la consistencia en la contaminación de bacterias dentro de los individuos de Parus major, comprando diferentes regiones del cuerpo (ventral vs dorsal) y comparando contaminación entre años. Números de bacterias viviendo libremente y adheridas y la riqueza de especies del ensamble de bacterias degradadoras de plumas fueron estudiadas usando citometria de flujo y análisis ribosomal intergenetico espaciado (RISA). Números de ambos tipos de bacterias fueron más elevados en el dorso que en las plumas ventrales. Números de bacterias viviendo libremente, pero no las adheridas, en las regiones del cuerpo estuvieron altamente y positivamente correlacionados. También hubo una fuerte correlación dentro del individuo entre los números de bacterias adheridos durante el mismo estado reproductivo en años diferentes. Estos resultados sugieren que a pesar de la variación absoluta en los niveles de las cargas de bacterias del plumaje entre años y diferentes regiones corporales, individuos muestreados pueden proporcionar estimativos consistentes en los niveles relativos de contaminación bacteriana, siempre y cuando los tiempos de muestreo y la región corporal sean cuidadosamente estandarizados.The Estonian Science Foundation (grant number ETF8566 to R.M. and ETF8376 to V.T.), the Estonian Ministry of Education and Science (target-financing project number SF0180004s09) and the European Regional Development Fund (Center of Excellence FIBIR).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1557-9263

Variación en el ensamble de bacterias de las plumas con relación al color del plumaje de la hembra de parus major

Microorganisms are known to play an important role in shaping the life histories of animals. Recent studies have proposed that the coloration of birds’ plumage could reflect individual quality through associations with feather-degrading bacteria. However, few studies have explored such relationships. We studied breeding female Great Tits (Parus major) during nest building and chick rearing to explore associations between bacteria inhabiting their yellow chest feathers and feather coloration. Specifically, we used flow cytometry and ribosomal intergenic spacer analysis (RISA), respectively, to study the densities of all free-living and attached bacteria and the phylotypic richness of feather-degrading bacterial assemblages. We used chroma (color saturation) as a measure of feather coloration. During chick rearing but not during nest building, the female’s chroma was negatively related to the phylotypic richness of feather-degrading bacteria. Also, a seasonal change in the density of attached bacteria associating with individual birds was negatively associated with change in chroma over the same period. These findings suggest that conspicuous coloration of female Great Tits may reflect the numbers and character of bacteria inhabiting feathers.Se sabe que los microorganismos juegan un rol importante en modelar las historias de vida de los animales. Estudios recientes han propuesto que la coloración del plumaje de las aves podría reflejar la calidad individual indicando la asociación con bacterias que degradan las plumas. Sin embargo, pocos estudios han explorado estas relaciones. Estudiamos hembras reproductivas de Parus major durante la construcción del nido y la cría de pichones para explorar asociaciones entre bacterias que habitan sus plumas amarillas del pecho y la coloración de las plumas. Específicamente, usamos citometría de flujo y análisis ribosomal de espaciadores intergénicos (RISA por sus siglas en Inglés), respectivamente, para estudiar las densidades de todas las bacterias libres y ligadas y la riqueza filotípica de los ensambles de bacterias que degradan las plumas. Empleamos croma (saturación del color) como una medida de coloración de la pluma. Durante la cría de los pichones pero no durante la construcción del nido, la croma de la hembra estuvo negativamente relacionada a la riqueza filotípica de las bacterias que degradan las plumas. Además, el cambio estacional en la densidad de las bacterias ligadas asociadas con aves individuales estuvo negativamente asociado con los cambios en la croma a lo largo del mismo período. Estos resultados sugieren que la coloración conspicua de las hembras de P. major puede reflejar la cantidad y el carácter de las bacterias que habitan las plumas.The Estonian Science Foundation (grant number ETF8566 to RM), the Estonian Ministry of Education and Science (target-financing project number 0180004s09), and the European Union through the European Regional Development Fund (Center of Excellence FIBIR).http://www.ucpressjournals.com/reprintInfo.asp.am2013ab201

Population differences in the length and early-life dynamics of telomeres among European pied flycatchers

Telomere length and shortening rate are increasingly being used as biomarkers for long-term costs in ecological and evolutionary studies because of their relationships with survival and fitness. Both early-life conditions and growth, and later-life stressors can create variation in telomere shortening rate. Studies on between-population telomere length and dynamics are scarce, despite the expectation that populations exposed to varying environmental constraints would present divergent telomere length patterns. The pied flycatcher (Ficedula hypoleuca) is a passerine bird breeding across Eurasia (from Spain to western Siberia) and migrating through the Iberian Peninsula to spend the nonbreeding period in sub-Saharan Africa. Thus, different populations show marked differences in migration distance. We studied the large-scale variation of telomere length and early-life dynamics in the pied flycatcher by comparing six European populations across a north-south gradient (Finland, Estonia, England and Spain) predicting a negative effect of migration distance on adult telomere length, and of nestling growth on nestling telomere dynamics. There were clear population differences in telomere length, with English birds from midlatitudes having the longest telomeres. Telomere length did not thus show consistent latitudinal variation and was not linearly linked to differences in migration distance. Early-life telomere shortening rate tended to vary between populations. Fast growth was associated with shorter telomeres in the early life, but faster nestling growth affected telomeres more negatively in northern than southern populations. While the sources of between-population differences in telomere-related biology remain to be more intensively studied, our study illustrates the need to expand telomere studies at the between-population level

Geographical Variation in Egg Mass and Egg Content in a Passerine Bird

Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca), by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk androgens and yolk total carotenoids. We found significant variation among populations in most egg components, but ca. 90% of the variation was among individuals within populations. Population however explained 40% of the variation in carotenoid levels. In contrast to our hypothesis, we found geographical trends only in carotenoids, but not in any of the other egg components. Our results thus suggest high within-population variation and leave little scope for local adaptation and genetic differentiation in deposition of different egg components. The role of these maternally-derived resources in evolutionary change should be further investigated.Peer reviewe

Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca)

Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female’s diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species’ geographical range. Further studies are needed to test the fitness effects of this geographical variation

The great tit HapMap project: a continental‐scale analysis of genomic variation in a songbird

A major aim of evolutionary biology is to understand why patterns of genomic diversity vary within taxa and space. Large-scale genomic studies of widespread species are useful for studying how environment and demography shape patterns of genomic divergence. Here, we describe one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning ~30 degrees of latitude and 40 degrees of longitude – almost the entire geographical range of the European subspecies. Genome-wide variation was consistent with a recent colonisation across Europe from a South-East European refugium, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear ‘islands of differentiation’, even among populations with very low levels of genome-wide differentiation. Low local recombination rates were a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination causes highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, probably as a result of recent directional selection at the species' range edges. Haplotype-based measures of selection were related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into spatio-temporal evolutionary dynamics

Plasma alkaline phosphatase as a sensitive indicator of age and skeletal development in wild coscoroba swans

Context. Recent studies have suggested that plasma alkaline phosphatase (ALP) can be used to assess skeletal development as well as health status in wild animals. Aims. However, the information about age-related dynamics of ALP in birds, especially in precocial species, is very scarce. Therefore, before ALP measurements can be effectively interpreted, it is necessary to determine its normal variation for each species, age group and sex. Methods. Here, we report total-ALP levels of free-living coscoroba swans (Coscoroba coscoroba) from the most important breeding and moulting population in Brazil. Data were gathered during the moulting period and categorised according to sex and the following three different age classes: chick (n=11), young (n=14) and mature (n=29). Key results. ALP levels were related to the longitudinal measure of the bones, gradually diminishing with age and showing significant differences among birds of different age classes. In all age groups, no effect of sex on T-ALP concentration was detected. Conclusions. We conclude that measuring ALP facilitates the discrimination among different-aged individuals with similar plumage characteristics and body size. © CSIRO 2010.Peer Reviewe